In general, defibrillation therapy is a process used to treat a patient experiencing heart fibrillation (i.e., where the heart experiences potentially fatal arrhythmias). The defibrillation process involves placing electrodes on the patient""s chest and applying defibrillation shock. The defibrillation shock is a brief biphasic pulse of electricity to the cardiac muscle applied to the patient""s bare chest to stimulate the heart and correct the fibrillation. The electrodes generally comprise an anode and a cathode, and come either as a single-use pads, or reusable paddles. The single-use pads are adhesive so as to adhere to the patient, and are thus hands-free. In contrast, the paddles do not adhere to the patient, and are therefore not hands-free.
In addition to providing defibrillation, cardiac defibrillators often provide caregivers with monitoring and additional therapy capabilities. Generally, a monitoring capability involves a passive use of the defibrillator to record signals generated by the patient. In contrast, a therapy capability involves injecting electricity or other signals into the patient. A monitoring capability often included in a defibrillator is electrocardiograph (ECG) monitoring. Therapy capabilities often included in a defibrillator include defibrillation, external cardiac pacing, and cardioversion with or without pacing. In order to perform the ECG monitoring, pacing, cardioversion including a pacing function, or defibrillation where the defibrillator indicates when a shock is to applied, extended electrical contact needs to be made to the patient. This extended contact is provided using the single-use pads, or the reusable paddles to the extent this is possible. Further, extended contact is often more practical for other therapy and monitoring capabilities.
FIG. 1 shows a defibrillation and monitoring system using self-adhesive, single-use pads 10. The defibrillator 1 is connected to the pads 10 by corresponding leads preconnected to the pads 10, and the pads 10 are then placed on the chest of the patient in predetermined positions. For defibrillation, the preferred location is for one pad 10 to be located on the upper-right sternal border of a chest of the patient, with one end near the clavicle and the other end just over the right nipple. The other pad 10 is located on the left side of the patient, wrapped from the back to the front under the left nipple and across the left midaxillary line. In this way, the pads 10 are placed to maximize current flow through the myocardium.
The pads 10 are generally constructed of a flexible metallic conductor plate sandwiched between a protective polymer backing and a conductive hydrogel adhesive that is used to adhere the pads 10 to the patient. The pads 10 also typically have a molded connector, or will have the leads molded into the pads 10, to connect corresponding leads to the defibrillator 1. An example of the pads 10 are the Heartstream pads produced by Agilent Technologies (part no. M3713A).
An advantage of single-use pads 10 is that the caregiver can adhere the pads 10 to the patient, and then administer the defibrillation shock without being in contact with the patient. This hands-free ability reduces the chance that the caregiver will be shocked by or otherwise exposed to the electrical pulse passing through the pads 10 during defibrillation. However, the pads 10 have drawbacks in that they are expensive to use, and they do not allow the caregiver to perform a quick look of the patient ECG in order to better assess the condition of the patient. A quick look generally is when a caregiver makes a temporary or abbreviated connection to the patient in order to obtain a quick reading of the patient""s heart rhythm or condition. Specifically, if the caregiver wants to use the pads 10 to check a condition of the patient, the pads 10 must be removed from their protective packaging (not shown), causing the hydrogel to become dehydrated and contaminated and making them unsuitable for an additional use.
FIGS. 2A and 2B show a conventional reusable paddle 20 which is one of two that are used instead of the pads 10 shown in FIG. 1. The paddles 20 include a handle 22, which the caregiver grips in order to place and maintain the paddle 20 at a predetermined location on the patient, and a conductor plate 24 through which the defibrillation shock is applied. In order to reduce the impedance caused by dry skin or other factors related to the patient, a conductive medium 26 such as a gel is normally placed on the conductor plate 24.
An advantage of using paddles 20 is that they are reusable. As such, the same pair of paddles 20 can be used again so long as the conductive medium 26 is removed and the paddles 20 are decontaminated and cleaned after use. However, the paddles 20 have drawbacks in that, in order to administer defibrillation, the caregiver must press the paddles 20 onto the patient. By having the caregiver be in close proximity to the patient, the caregiver is exposed to a shock hazard during defibrillation. In addition, the use of the conductive medium 26 creates a mess both on the paddles and the patient, increases the chance of shock to the caregiver, and makes the paddles 20 difficult to clean and decontaminate. Further, the paddles 20 are relatively large and heavy in comparison to the pads 10. Lastly, since the paddles 20 are not attached to the patient, the paddles 20 cannot be used or are not practical for use in ECG monitoring, for external cardiac pacing, for cardioversion where pacing is performed, or for automatic ECG interpretive algorithms defibrillators (automatic external defibrillators) that indicate when a shock is to be delivered because these functions require the electrodes to be in extended contact and a motion free relationship with the patient. An example of the reusable paddles 20 is the part no. M4746A produced by Agilent Technologies.
For additional information on the use and placement of pads 10 and paddles 20 in conjunction with a defibrillator 1 having monitoring capabilities, reference is made to the Agilent M4735A Heartstream XL Defibrillator/Monitor User""s Guide (Agilent Technologies) (Edition 1, September, 2000), which is incorporated herein by reference.
According to an embodiment of the present invention, a paddle for use with a defibrillator includes an applicator, a pad portion electrically connected to the applicator and having a conductive medium removably encased in the pad portion, and an electrical contact electrically connected to one of the applicator or the pad portion, the electrical contact being exposed while the conductive medium is encased in the pad portion.
According to another embodiment of the present invention, an applicator for use with an adhesive pad to form a paddle for use with a defibrillator includes a main body having a bottom, a connector on the bottom to electrically and mechanically attach the main body to the adhesive pad along a primary electrical path between a patient, the main body and the defibrillator, a handle attached to the main body, and an electrical contact attached to the main body to form a secondary electrical path between the patient, the main body and the defibrillator.
According to still another embodiment of the present invention, a pad portion for use with an applicator to form a paddle for use with a defibrillator includes a backing having a top and a bottom, a connector attached to the top to form a mechanical and electrical connection to the applicator, a conductive medium attached to the bottom, a lid to encase the conductive medium, and an electrical contact disposed on the lid to provide an electrical pathway to the applicator when the conductive medium is encased by the lid.
According to yet another embodiment of the present invention, a method of using a paddle with a defibrillator includes attaching a pad portion to an applicator portion to form the paddle, the pad portion having a conductive medium encased by a lid, assessing a condition of a patient by forming an electrical pathway between the defibrillator and the patient using an electrical contact disposed on the lid or the applicator, and removing the lid to connect the paddle to the patient to form another electrical pathway between the defibrillator and the patient.
According to a further embodiment of the present invention, a paddle for use with a defibrillator includes an applicator having a flexible plate that shapes to a curvature of a patient, a handle attached to a top of the flexible plate, and an applicator connector disposed on a bottom of the flexible plate; a pad portion electrically connected to the applicator, having a flexible backing that is shaped by the flexible plate, a pad portion connector disposed on a top of the flexible backing to form an electrical and mechanical connection to the applicator connector, a lid attached to the flexible backing, and an adhesive conductive medium attached to a bottom of the flexible backing and removably encased by the lid, the adhesive conductive medium comprising a flexible conductor disposed between an adhesive layer and the flexible backing; and an electrical contact disposed on the lid electrically connected to the pad portion, the electrical contact being exposed while the adhesive conductive medium is encased by the lid so as to send signals to said applicator through the conductive medium.
According to a still further embodiment of the present invention, a paddle for use with a defibrillator includes an applicator having a flexible plate that shapes to a curvature of a patient, a handle attached to a top of the flexible plate, and an applicator connector disposed on a bottom of the flexible plate; a pad portion electrically connected to the applicator, having a flexible backing that is shaped by the flexible plate, a pad portion connector disposed on a top of the flexible backing to form an electrical and mechanical connection to the applicator connector, an adhesive conductive medium attached to a bottom of the flexible backing, the adhesive conductive medium comprising a flexible conductor disposed between an adhesive layer and the flexible backing, and the adhesive conductive medium being shaped to be removably encased by a bag; and an electrical contact disposed on the flexible plate adjacent to the applicator connector so as to form an additional electrical pathway between the defibrillator and the applicator while the pad portion is not connected to said applicator.
According to a yet further embodiment of the present invention, a paddle for use with a defibrillator includes an applicator having a flexible plate that shapes to a curvature of a patient, a handle attached to a top of the flexible plate, and an applicator connector disposed on a bottom of the flexible plate; a pad portion electrically connected to the applicator, having a flexible backing that is shaped by the flexible plate, a pad portion connector disposed on a top of the flexible backing to form an electrical and mechanical connection to the applicator connector, an adhesive conductive medium attached to a bottom of the flexible backing, the adhesive conductive medium comprising a flexible conductor disposed between an adhesive layer and the flexible backing, and a layer removably encasing the adhesive conductive medium; and an electrical contact disposed on the flexible plate adjacent to the handle so as to form an additional electrical pathway between the defibrillator and the applicator while the adhesive conductive medium is encased by the layer.